London-based Peak has raised $7 million for its brain training app, in a round led by Creandum with participation from DN Capital, London Venture Partners, and Qualcomm Ventures.

"Since we launched last September, Peak has been used by millions of people all over the world," the company wrote in a post on Medium. "The investment will help us to map the world’s cognitive performance, providing individuals with a way to test, track and train their cognitive functions."

The app, available on iOS and Android devices, aims to help users improve their memory, focus, problem solving, mental agility, and language skills. There are 24 games available on the app which range in difficulty level. Some of the exercises are personalized for each user. The app will also offer performance reviews and analytics based on how well the user is doing and help users set personalized goals for themselves.

According to the company, Peak is designed in collaboration with experts in neuroscience, cognitive science, and education. Peak's scientific advisors include Emeritus Professor and Yale Senior Research Scientist Bruce Wexler as well as Twiggle Cofounder Amir Konigsberg.

While the app is free to download, the program costs $4.99 for one month and $34.99 for 12 months.

There are a number of companies that have similar mobile brain training offerings, like Lumosity, but some companies have taken brain training games one step further. Boston-based Akili Interactive Labs has been working on a gaming app that will help diagnose and treat cognitive conditions including autism, Alzheimer’s, and ADHD. Akili has partnered with pharma companies in the past, including Shire and Pfizer, to validate these offerings.

However, it's also a risky time to be in the brain training field, or at least a time for companies to be careful what claims they make. In January, the Federal Trade Commission announced an administrative complaint against Focus Education, a company that makes a brain training game for children called Jungle Rangers. The complaint charges that the company advertised permanent brain improvements in “focus, memory, attention, behavior, and/or school performance”, including for children with ADHD, and backed up the claims with what the FTC said were nonexistent scientific studies.